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Hispano-Suiza 12Y
The Hispaon-Suiza 12Y was a 12 cylinder vee inline aero engine developed by France in 1932. Page 160 History Development The 12Y was a development of the earlier 12X. The new engine had master-rod and articulated link-rod type connecting rods of tubular design, made from nickel-chrome steel. The bore was 5.9 in (150 mm) and stroke was 6.69 in (170mm), giving the 12Y a cubic capacity of 2,198 cu in (36 litres). The steel cylinder barrels, which had nitrated bores, were located in the cylinder by a special steel sealing ring in the head and two rubber sealing rings when they were clamped to the crankcase. Cylinder block coolant went via an external pipe to a connection on the cylinder heads, feeding a pierced longitudinal pipe fitted inside inside the blocks, which allowed dispersion of coolant to the hottest points within the engine. As in previous Hispano-Suiza engine designs, the exhaust ports for the cylinder heads were spaced in 1, 2, 2, 1 layout, with inlet and outlet ports on the outer side of the blocks. The pistons were forged from aluminium with low expansion co-efficient, while the six throw camshaft was a one-piece forging made from nickel-chrome, which was carried on eight bearings, with a torsional vibration dynamic damper at each end. Each individual cylinder was served with one inlet valve and one outlet valve, which were forged from sodium filled hollow chromium silicon steel. Built in a number of variations, such as the 12YCrs designed with fittings for a 20 mm Hispano-Suiza HS.404 autocannon, the 12Y was a single stage engine of modest output, with spur gear type reduction gear, and a propeller shaft carried in plain bearings with two ball-bearing thrust races. Bingham, Victor. 1998. Page 161. In late 1936 and early 1937, the connecting rods were changed to I cross section. This led to the 12Y-33, which produced 850 hp at 2,400 rpm on take off, for a dry weight of 1,80 lb (490 kg). In 1938 Hispano-Suiza introduced the 897 hp 12Y-45, which had it's Hispano-Suiza supercharger replaced with a Szydlowski-Planiol S-39-H3 unit, in an attempt to improve the engine's performance at high altitude. This was followed by the 12Y-49, which developed 850 hp at 2,400 rpm at sea level and 920 hp at its rated altitude.Bingham, Victor. 1998. Page 162. The 12Y series were followed in 1939 by the 12Z series,Bingham, Victor. 1998. Page 163. and also served as the basis for the Klimov VK-105. Specification Standard data is for the 12Ydrs 2 version, with bore and stroke of 5.9 x 6.69 in (150 x 170 mm), and displacement of2,197 cu in (36 litres). This measured 5 ft 5in (1.722 m) in length, 2 ft 7 in (0.764 m) in width and 3 ft 0.5 in (0.935 m) in height. Compression ration was 5.8:1, with reduction gear ratio of2:3 and supercharger gear ratio of 9.38:1. Dry weight was 1,036 lb (470 kg), and maximum take off power was 980 hp at 2,400 rpm at sea level. Rated power at 2,400 rpm was 890 hp at sea level and 930 hp at 2,950 ft, using 85 octane fuel. The final version of the 12Y, the 12Y-51, differed from the 12Y drs 2 through increased compression ratio of 7:1, dry weight of 1,146 lb (520 kg) and supercharger gear ratio of 10:1. The 12y-51 used 100 octane fuel, resulting in maximum take of rating of 1,084 hp at 2,500 rpm and nominal power rating of 986 hp at 10,620 ft. References Category:Engines Category:Aircraft Engines Category:French Engines